Can I use one two stage thermostat to control two separated single stage RTU

[williamxia]

I am trying to use one two-stage stat to control two RTU , so that they can work just as one two-stage RTU

Can somebody can let me know how to connect the wire?

Thank you ahead

[Mstrav]

yes i have all the info right here:
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oh wait, i get paid $$$$ for this info, call a tech out. This is not the purpose of this forum sorry, but to answer your question, YEP!!!

matt

[HVAC Teacher]

:)

[williamxia]

answer me please,
I would appreciate you
regards

[cw0682]

Williamxia, your going to have a rough time finding step by step how to information here in these forums. These forums can be very educational, but this is not a DIY haven either.

We suggest getting an expierieced tech with you wiring as we would really hate to see you hook something up and blow up a transformer or make your units do stuff they are not suppose to do.

The answer to your question is yes it can be done, not sure why you would want to do it but yes it can be done.

[refrigerationtech]

i tell ya but then it put me out of $$$ choices choices... what to do...

[atmosphere]

Strip the appropriate wire with a wire stripper.
Make a Semi circle loop and attach it to the proper lug on the terminal board.

Not a big deal.

[Airmechanical]

yes you can do it!

good idea!

good luck!



.

[Randy S.]

We all started someplace, somewhere.:eek:

You will need to use a relay to switch the second unit on, and keep the two low voltage sources isolated. Have the second stage operate the relay, and the relay contact(s) operate the other unit.

[johnl45]

We all started someplace, somewhere.:eek:

You will need to use a relay to switch the second unit on, and keep the two low voltage sources isolated. Have the second stage operate the relay, and the relay contact(s) operate the other unit.

If they understand that-------------it shoud be no problem.

[williamxia]

Thank your guys

[dreo0010]

use two stats better

[makinmoney]

I am trying to use one two-stage stat to control two RTU , so that they can work just as one two-stage RTU

It will work but what is there now? 2 RTU's with their own ductwork feeding 2 different areas? If one is feeding interior space and one is feeding perimeter space, you could end up with a problem.

[idratherbsailing]

i'd set it up to alternate lead-lag

[wefixes]

Have your tech. phase the two transformers together, then from the thermostat, wire one unit to
Y1, W1, the other unit to Y2, W2. Wire G to G to G. Wire C to C to C. Wire R to R to R.
The indoor blower motor will run on both units on call for fan or cooling.
Done it before, it works. Check secondary amperage through stat on all modes
to make sure not exceeding rating. Or do what Randy says.
Dont try this at home, use someone elses equipment!

[DarthHVAC]

install relays to bring the coils in with a call from W2, y2, and G. The small load of the isolation relays will not disturb the thermostat.